1. Field of the Invention
The present invention relates to a work table having integral lateral and longitudinal cutting guides and a detachable cutter.
2. Background Art
Workers in the sheet metal fabricating trades cut panels and layout complex folded pieces on site. Vinyl sheet stock including pieces of vinyl and coils of vinyl are increasingly being used in place of sheet metal. References to sheet metal in this application should be deemed equally applicable to vinyl sheet stock. Sheet metal is used in making soffit, fascia, roof panels and aluminum siding trim. Sheet metal supplied in coil form is cut to the desired size and then marked to locate bends and folds in the part required to make J-channel shapes, brick molding, and the like. Workers generally layout these complex shapes on the ground, on make shift tables, or on top of a bending brake.
When working with elongated sheets of sheet metal that may be twelve feet in length it is difficult to precisely locate cuts and bends and it is difficult to make accurate cuts, particularly along the length of a long sheet metal piece. If inaccurate cuts or bends are made, scrap costs and material waste increase. Also, the quality of parts fabricated may be adversely impacted.
There is a need for a portable work table for use at job sites that facilitates cut off of blanks, layout and formation of complex sheet metal shapes. The present invention addresses this need and the above problems as summarized below.
According to one aspect of the present invention, a portable work table is provided for working on sheet metal. The portable work table includes a stand and a table top that is supported on the stand. The table top may be described as having front and rear longitudinally extending edges and first and second transversely extending edges. A transversely extending guide rail is secured near the first transversely extending edge of the table. The guide rail is shifted between the first position in which the guide rail is spaced above the piece of sheet metal to be fabricated and a second position in which the guide rail is held to clamp the sheet metal against the table. A backstop may be provided near the rear edge of the table. A removable cutter supported on the guide rail on bearings or other rolling elements and has a knife that is positioned to cut sheet metal supported on the table in alignment with the first transversely extending edge of the table.
According to another aspect of the invention a portable work table as described above may further feature a longitudinally extending guide rail secured near the front longitudinally extending edge of the table top. The longitudinally extending guide rail is moveable between a first position in which the guide rail is spaced above the sheet metal on the table and a second position in which the guide rail is held against the piece of sheet metal on the table. The removable cutter may be supported on either the longitudinally extending guide rail or the transversely extending guide rail to make transverse and longitudinal cuts in the sheet metal.
According to other aspects of the present invention another rail may be connected to the longitudinally extending guide rail at the opposite end from the transversely extending guide rail. The transversely extending guide rail, longitudinally extending guide rail and rail are connected together and are pivotally connected to the table at a point near or on the backstop to form a three-sided pivotal frame. The frame defines an open area on the table top for laying out and aligning the sheet metal piece.
Other aspects of another embodiment of the invention include securing the transversely and longitudinally extending guide rails to the table by means of a plurality of pins so that the guide rails are vertically moveable. At least one and preferably a plurality of springs may be used to bias the guide rails away from the table to provide clearance between the table and the guide rails. Clearance is provided to allow the sheet metal to pass beneath the guide rails on the table top. At least one clamp is provided to releasably lock the guide rails in their second position to clamp the sheet metal against the table.
Other aspects of the invention relating to removable cutter include providing a removable cutter that includes a carriage and a pair of roller cutter knives that are positioned to cut the sheet metal on the table as the cutter is moved along the transversely extending guide rail and/or the longitudinally extending guide rail. A removable cutter may alternatively comprise a carriage and a roller cutter knife that is positioned to cut sheet metal on the table as the cutter is moved along the transversely or longitudinally extending guide rails. The roller knife is held so that it engages a knife edge on either the first transverse extending edge of the table or on the longitudinally extending edge of the table top. Alternatively, a scoring knife could be used instead of a roller knife and should be deemed an equivalent.
Another aspect of the invention relates to the concept of providing a bending flange that may be secured to the longitudinally extending edge of the table by a hinge. The bending flange is raised to bend a portion of the sheet metal overhanging the longitudinally extending edge of the table.
Another aspect of the invention relates to providing a coil holder that is connected to the table outboard of the first transversely extending edge of the table from which a roll of sheet metal may be dispensed onto to the table through a space formed between the table and the first transversely extending guide rail. A length of sheet metal may be measured with reference to measurement indicia on the portable work table and cut off to form a desired length of sheet metal. Alternatively, the coil holder may be provided separate from the table and positioned outboard of the first transversely extending edge of the table. The sheet metal may be dispensed from the coil, measured and cut off on the table. Transverse measurement indicia are also provided on the table top to facilitate laying out a piece of sheet metal for subsequent cutting and bending operations. The backstop secured to or near the rear edge of the table top may be used to align and orient sheet metal on the table top.
According to another aspect of the invention, the pair of longitudinally extending beams may be provided to which the table top is secured. The beams are specialized extruded beams having an upper side including a raised longitudinally extending central portion that is flanked by one or two relatively lower shoulder portions. The front longitudinally extending edge of the table is received on one shoulder portion. A first knife edge may be secured to one of the shoulder portions with a second knife edge being secured between two shoulder portions of the two longitudinally extending beams so that the second knife edge is aligned with the first transversely extending edge of the table top. The beams may also include a rib to which the stand may be detachably secured.
According to the present invention, a work table is provided that features a table top having a longitudinally extending front side, a longitudinally extending back stop, and two laterally extending side edges. A first cutter guide is attached adjacent to the front side of the table top, and a second cutter guide is attached adjacent to one of the side edges. A detachable cutter is usable with one or both of the first and second guides.
According to another aspect of the invention, the table top may have gridlines painted or embossed thereon to assist in measuring and aligning work pieces on the table top. In addition, the table top may have quick reference templates or instructions for forming sheet metal shapes on the top surface of the table top, either with or without the gridlines.
According to another feature of the invention, the first guide attached to the front side of the table top is provided by a rail that extends parallel to a linear knife edge that extends substantially across the entire length of the front side. The rail providing the first guide is secured at its ends to the table and may have cam clamps inboard of the end attachments that flex the rail downwardly to clamp the material to be cut against the table. The second cutter guide is provided by a rail attached adjacent to one of the side edges and that is parallel to a second linear knife edge that extends across one of the side edges of the table top.
The cutter of the present invention has a set of rail engaging rollers that engage the first and/or second cutter guides. The cutter also preferably includes a circular knife that cuts sheet material when the cutter is moved along the first or second cutter guide and engages one of the linear knife edges.
The present invention also may encompass providing a coil holder, that is retained either adjacent to a side edge of the table top, supported on extended rails adjacent the table top, or suspended from the bottom of the table top so that sheet material may be fed from the coil over one of the side edges to the upper surface of the table top.
The above objects and advantages and other features of the invention will be apparent to one of ordinary skill in the art in view of the attached drawings and description of the best mode below.